Ground effect machine pressure fluid cushion confining walls

ABSTRACT

A ground effect machine having at least one cushion comprises juxtaposed elementary skirts each fed with pressure fluid, the edge by which each of these skirts is fixed on the machine comprising two substantially rectilinear and opposite elements in such manner that two adjacent skirts touch along their height by a portion of their substantially plane wall. The tension of the skirts, which ensures their stability of shape despite the slight difference between their fixing section and their opening section, is obtained by means of a permeable wall fixed towards the bottom of the skirt and formed with fluid passages the sum of the sections of which is less than the section of the skirt supply conduit so as to maintain a fluid pressure in the top part of the skirt. The permeable wall is designed and adapted to inflate under the effect of said tension and have a curved profile with its convexity directed towards the contact surface which the machine cooperates.

United States Patent Bertin GROUND EFFECT MACHINE PRESSURE FLUID CUSHIONCONFINING WALLS [75] Inventor: Jean Henri Bertin,

Neuilly-Sur-Seine, France [73] Assignee: Bertin & Cie, Plaisir. France[22] Filed: Sept. 4, 1973 [21] Appl. No.: 394,056

[30] Foreign Application Priority Data Sept. 5. 1972 France 72.31401[52] US. Cl 180/121; 180/128 [51] Int. Cl. B60v 1/04 {58] Field ofSearch 180/121, 127, 126, 124, 180/116, 117,128

[56] References Cited UNITED STATES PATENTS 3,267.882 8/1966 Rapson etal. [80/124 X 3.272.275 9/1966 Faure 180/127 3.369.623 2/1968 Bertin180/127 3,414.075 12/1968 Bertin 180/121 31131938 1/1972 Eggington180/121 Primary Examinerl(enneth H. Betts Attorney, Agent, or FirmA. W.Breiner 5 7] ABSTRACT A ground effect machine having at least onecushion comprises juxtaposed elementary skirts each fed with pressurefluid, the edge by which each of these skirts is fixed on the machinecomprising two substantially rectilinear and opposite elements in suchmanner that two adjacent skirts touch along their height by a portion oftheir substantially plane wall. The tension of the skirts, which ensurestheir stability of shape de spite the slight difference between theirfixing section and their opening section, is obtained by means of apermeable wall fixed towards the bottom of the skirt and formed withfluid passages the sum of the sections of which is less than the sectionof the skirt supply conduit so as to maintain a fluid pressure in thetop part of the skirt. The permeable wall is designed and adapted toinflate under the effect of said tension and have a curved profile withits convexity directed towards the contact surface which the machinecooperates.

4 Claims, 10 Drawing Figures PATENTE m 1 91975 SHEET 1 BF 2 GROUNDEFFECT MACHINE PRESSURE FLUID CUSHION CONFINING WALLS This inventionrelates to a means for confining a pressure fluid cushion for a groundeffect machine cooperating with a bearing surface along which it canmove, the said means enabling appreciable pressures to be containedwhile having great flexibility in a direction substantiallyperpendicular to the said surface.

Ground effect machines are known which have a platform or otherstructural part and which move with respect to a bearing surface withthe interposition of a pressure fluid cushion system making use of oneor, preferably, more flexible bodies secured to the said structure fromwhich they project in the direction of the said bearing surface as faras a free end adjacent the latter. each flexible body being formed onthe one hand by an endless fluidtight wall forming a skirt and, on theother hand, a transverse partition which is permeable to the said fluidand connected peripherally to the said endless side wall near the saidfree end so as to define a first space directly fed with pressure fluidand extending from the said structure to the said transverse partition.and a second space fed by the fluid after it has passed through the saidpartition and extending from the latter to the said bearing surface.

Flexible bodies of this kind are known wherein the permeable transversepartition is designed to produce an appreciable pressure loss as thesaid fluid passes through it and is therefore subjected to a relativeexcess pressure which biases it in the direction of the said bearingsurface, the extension of the said flexible body in the direction ofthhe said bearing surface being ensured essentially by the said relativeexcess pressure which is exerted on the said permeable transversepartition.

This procedure, which comprises tensioning or stressing the fluidcushion confining walls by a means specifically introduced for thatpurpose, is particularly suitable for cases in which the confining meanscomprises flexible tubular skirts individually receiving the fluid whichtakes part in lifting the machine.

It has been found that even when appreciable pressures are applied inthe inner fluid cushion space, thereby urging such tubular skirtsoutwardly, the latter no longer tend to be outwardly deflected, andtherefore retain their effectiveness.

The object of the present invention is to provide a system of contiguousindividual skirts disposed consecutively along the entire periphery ofthe machine structure in order to confine therein an inner pressurefluid cushion.

To embody such a system, it has already been proposed to use skirtshaving a evolutive shape i.e., a shape developing from a square orpolygonal section at their end fixed to the structure of the machine, toa substantially circular or round section at the opposite free endadjacent the bearing surface (see Bertin US. Pat. Nos. 3,369,623 and3,414,075).

The perimeter by which skirts of this kind are fixed on the machinestructure is characterised in that it comprises two substantiallyrectilinear and opposite elements so that two adjacent skirts are inmutual contact engagement over their height along a substantially planewall portion. The remainder of the fixing perimeter between these twoopposite rectilinear elements may comprise two connecting rectilinearelements so that the perimeter forms a square or like geometric figure.

The invention is particularly advantageous with skirts of this kindbecause, since two adjacent skirts must touch along a substantiallyplane wall, these skirts cannot be given a marked tapered shape and sothe pressure of the fluid contained in the skirt has practically noeffectiveness to keep the skirt inflated and extended as is the casewith conical skirts whose opening area may be much smaller than that oftheir fixation end (see Bertin, US. Pat. No. 3,388,766).

If skirts of this no-or small-taper kind are provided with a transversepartition causing a pressure loss, and bulging towards the bearingsurface, then the internal action of the pressure and tension in thedownward direction as exerted on these skirts results verysatisfactorily in inflation of the skirts and good reciprocalapplication of the adjacent skirts together with good resistance tocrushing and effective damping of the impact of the waves in case of awater going vehicle.

The invention will be more readily understood from the followingdescription with reference to the accompanying drawings, which is givenby way of example.

FIG. I is a diagrammatic cross-section on the line II in FIG. 2 showinga skirt provided with the improvement according to this invention.

FIG. 2 is a longitudinal section of this skirt on line 11-" in FIG. 1.

FIG. 3 is a diagrammatic bottom plan view of a ground effect machineprovided with contiguous individual skirts confining an inner cushion.

FIG. 4 is a diagrammatic longitudinal section on the line IV-IV in FIG.3.

FIG. 5 is a partial longitudinal section to an enlarged scale, similarto that in FIG. 2, of the system of skirts shown in FIGS. 3 and 4.

FIG. 6 is a cross-section of the line VIVI in FIG. 5.

FIG. 7 is a diagrammatic longitudinal section of a alternativeembodiment according to this invention.

FIG. 8 is a bottom plan view on the line VIII-VIII in FIG. 7.

FIGS. 9 and 10 are diagrammatic longitudinal sections of two otheralternative embodiments.

Referring to the drawings, a skirt 1 is fixed at 2 beneath a groundeffect machine 3 and receives pressure fluid from a supply conduit 5 viaan orifice 4 formed in the machine.

The skirt 1 comprises a main tubular body 6 which extends towards thebearing surface 7 and the cloth of which is tensioned mainly by apermeable transverse partition 8 which produces appreciable pressureloss and is fixed peripherally towards the end of the main body 6 remotefrom the machine structure 3. Passages of calibrated section 8d areformed in the partition 8, the sum of the sections of the said passagesbeing less than the section of the supply conduit 4.

To protect the permeable transverse partition 8 against wear or tearingdue to contact with the surface 7, the main body 6 is extended in thedirection of the latter by a flexible tapering end 9.

The skirt is of evolutive configuration which is sometimes known as asquare-round skirt" of the type described in Bertin, US. Pat. No.3,369,623 and suitable for juxtaposition with like skirts to constitutea system of contiguous skirts. In plan view it has a polygonal, forexample square, shape at its end 2 connected to the machine structure 3,and a substantially circular shape at its free end adjacent the bearingsurface 7. More generally, the perimeter of its end 2 fixed to themachine structure has two opposite sides a b and c d which aresubstantially rectilinear and parallelto one another. Also, laterally ithas a substantially plane portion 11 of a general trapezoidal shapebearing on'one of the rectilinear side-a b and c d, which affordsefficient contact engagement with the corresponding adjacent planeportion of a contiguous skirt.

In the case ofa peripheral assembly ofjuxtaposed individual skirts Iwhich bounds an inner cushion space 12, the diameter of circle 10 may besubstantially equal to, or alternatively slightly greater than, the sideof the square 2. In this way the contiguous skirts have larger wallareas in mutual contact engagement, and this improves sealing-tightnessand the efficiency of the peripheral confining assembly. Also, thecushion fluid wetted area on the bearing surface 7 and hence thestability of the machine is increased.

According to this invention, each skirt is provided with a pressure lossentailing permeable partition 8 formed by a flexible web which, underthe effect of the pressure, inflates to have a profile with itsconvexity facing the bearing surface 7.

The web 8 is required to exert on the skirt 1 a force directedsubstantially along the wall of the said skirt, the effect of this beingnot only to stretch the skirt towards the bearing surface 7 but also toincrease its resistance to transverse crushing.

It should also be noted that the convex permeable web 8 can, as a resultof its flexibility, undergo deformation under the effect of an impactdirected towards the machine structure 3, for example that of a strongwave. In this way it forms a means of damping such an impact, and thisprovides effective protection, particularly of the supply means.

Finally, the fixing of the permeable flexible web 8 on the skirt 1 whichis itself formed by a flexible wall can be carried out simply (forexample by sewing, glueing' etc.,). In this way it is possible to use aweb 8 which is fixed solely to the skirt 1 over its periphery at (FIGS.7 and 8).

However, in the case of a skirt having a large diameter and if it isdesired to satisfy the above conditions, the magnitude of deflection ofthe web 8 is liable to be excessive. It can then be given a cusp, forwhich purpose it may be connected by one or more tie-rods 13 to thestructure of the machine 3.

In this way, in accordance with the embodiments shown in FIGS. 9 and 10,the web 8 is connected to the machine 3 at a single fixing point 14.

According to another embodiment (FIGS. 1 to 6), the permeable partition8 is made in three parts:

a rigid or relatively non-deformable ring 8a connected to the machinestructure 3 by tie-rods 13a.

a central permeable wall 8b fixed to this ring.

a peripheral permeable flexible web 80 fixed on the one hand to the ring8a and on the other hand to skirt I, said peripheral portion having apart toric shape.

FIGS. 1 and 2 illustrate a square-round skirt provided with such apressure-loss entailing permeable partition 8. The area of the square 2may be greater than that of the circle 10 although the diameter of thelatter is slightly greater than the sides of the square.

FIGS. 3 and 4 are diagrammatic views of an assembly of contiguoussquare-round individual skirts of the kind shown in FIGS. 1 and 2, whichbound an inner cushion 12.

FIGS. 5 and 6 are views of this confining assembly to an enlarged scale.The skirts are pressed against one another.

We claim:

1. A ground effect machine having a rigid frame movable along a bearingsurface with the interposition of pressure fluid cushions, comprising:

a plurality of individual skirts depending from said frame injuxtaposition next to each other along the periphery of said frame toform by their overall succession a peripheral enclosure for an innercushion space between said frame and said bearing surface, each of saidskirts having two opposite smooth side wall portions which aresubstantially planar and which extend from said frame over a substantialfraction of the overall extension of the skirt towards said bearingsurface, said skirts being fitted so that the adjacent planar smoothwall portions of contiguous skirts tightly apply against each other inareal contact engagement, and

a fluid permeable flexible partition extending transversely across eachskirt between those ends of the two opposite planar smooth wall portionsthereof which are remote from said frame, said fluid permeable flexiblepartition being designed for offering some resistance to fluid flowtherethrough from the inside of the skirt towards said bearing surfacethereby causing a pressure drop upon traverse by said fluid flow andbulging towards said bearing surface to develop a force which extendsthe skirt away from said frame and stretches likewise both the planarsmooth wall portions thereof.

2. Machine as claimed in claim 1, wherein said fluid permeable flexiblepartition comprises an incorporated rigid ring inwardly spaced from theskirt wall portion andbraced to said frame, whereby said flexiblepartition presents a multi-cusp outline with an inner bulging sectionsurrounded by said rigid ring and an outer bulging section intermediatesaid ring and said skirt wall portion.

3. Machine as claimed in claim 2, comprising a plurality of ties bracingsaid rigid ring to said frame and connected to spaced points distributedperipherally along said ring.

4. Machine as claimed in claim 3, wherein said outer bulging section isof part toric shape.

1. A ground effect machine having a rigid frame movable along a bearingsurface with the interposition of pressure fluid cushions, comprising: aplurality of individual skirts depending from said frame injuxtaposition next to each other along the periphery of said frame toform by their overall succession a peripheral enclosure for an innercushion space between said frame and said bearing surface, each of saidskirts having two opposite smooth side wall portions which aresubstantially planar and which extend from said frame over a substantialfraction of the overall extension of the skirt towards said bearingsurface, said skirts being fitted so that the adjacent planar smoothwall portions of contiguous skirts tightly apply against each other inareal contact engagement, and a fluid permeable flexible partitionextending transversely across each skirt between those ends of the twoopposite planar smooth wall portions thereof which are remote from saidframe, said fluid permeable flexible partition being designed foroffering some resistance to fluid flow therethrough from the inside ofthe skirt towards said bearing surface thereby causing a pressure dropupon traverse by said fluid flow and bulging towards said bearingsurface to develop a force which extends the skirt away from said frameand stretches likewise both the planar smooth wall portions thereof. 2.Machine as claimed in claim 1, wherein said fluid permeable flexiblepartition comprises an incorporated rigid ring inwardly spaced from theskirt wall portion and braced to said frame, whereby said flexiblepartition presents a multi-cusp outline with an inner bulging sectionsurrounded by said rigid ring and an outer bulging section intermediatesaid ring and said skirt wall portion.
 3. Machine as claimed in claim 2,comprising a plurality of ties bracing said rigid ring to said frame andconnected to spaced points distributed peripherally along said ring. 4.Machine as claimed in claim 3, wherein said outer bulging section is ofpart toric shape.